The present invention refers to a brewing device for the preparation of beverages, in particular hot beverages such as coffee, tea, roasted-barley coffee, camomile tea and similar brews and infusions, which makes use of compressed air for filtering and mixing the substances that make up the beverage.
Brewing devices of the above-indicated kind are largely known in the art and substantially comprise a vertical cylindrical body, in which the substances in powder form and the water are introduced through a filling hopper, arranged above the cylinder, and are mixed-filtered by air being admitted under pressure thereinto. These devices enable beverages to be obtained, which are thoroughly homogenized and may be more or less flavoured or tasty, and possibly more or less frothy, according to the actual requirements of the buyers.
A brewing device of this kind is for example described in the Japanese patent publication JP-A-01-158592. The device disclosed in this Japanese patent provides for the possibility for compressed air to be let into the brewing cylinder through two different conduits, which debouch into the lower-side portion and the upper-side portion of the cylinder, respectively. The two conduits are selectively opened by means of a three-way flow-diverting valve installed in the conduit that connects the air pump with the brewing cylinder.
The opening that establishes a communication between the filling hopper and the brewing cylinder is closable by a valve performing a reciprocating motion as driven by a specially provided motor. The solution described in this Japanese patent turns however out as being rather complicated from a structural point of view, as well as scarcely reliable from an functional point of view; it in fact calls for a number of different operating parts to be used, which imply quite high costs due to both the components and the assembly thereof.